Apparatus for reaming wells



March 7, 1950 F. w. HARRIS APPARATUS FOR REAMING WELLS 2 Sheets-Sheet 1 Filed May 27, 19

Patented Mar. 7, 1950 ,ieeie U N I TE D .S TATES PATENT "F F IQ E wkBBAiRATUS I'FDR REAMI-NG WELLS Ford W. Harris, Los Angeles, "Calif.

AnplinatiomMayiz'l, 1946,1Serial No.:672 ,498

!.Claims.

1 .jMy invention :relates to [the art pf drilling wells, and, since it :has a special :utility when used inpdeep oil wells although it isapplicable to .other uses, the following description will the principallydirected to the use of thelinvention 1111011 wells.

My invention relates to the art "of drilling wells and is particularly useful in drilling 'wells by the rotary-system ;in which .a string -..of drill pipe is rotated in the well by means :of a rotary table on the derrick rfloor above the well. The .lower end-of the string TOf drill pipelcarries a bit .WhlChClltS orfmakesiholeWasitis rotated and rotary mud, 'a watersuspension pf .clay 01 other :finely divided solid material, :is pumped down walls'of the well. 'Rotarymeamerslarewell-known .in the "art.

It is often-desirable after leasing, used to line "the wall of the well, has been set :in place .and the lower "end cemented, to ream or enlarge -,the

diameter of'the hole belowthe casing to aediam ieter greater than the inside diameter :of the cas Iing, this operation being :known as .underreaming. It is .a further v.object o'f my .-invention to provide a rotary underreamer' 'for this purpose.

Rotary underreamers must be, and .are mow, so made that the cutters thereof may be retracted xinto such a positionthat'the reamer may pass downwardly through the -;casing already .set in the :well, then expanded to -a position in .which they will cutthewall ofthewelltoza largeridiam- 'eter than therinsidezdiameter 11f the casing, .and then retracted to *their loriginal position -so :that

the .und'erreamer maybe readily withdrawn upwardly :through .the. casing. .IRotary .underreamers that -.so operate ;are well Jmown in ..the tart, randaunderreamers eembodying:myiinventionlhave this .old. method of operation.

,My invention Iolifiers from those snow "known f in theart .in that theicutters of .underreamers em- ,l'bodying myiinvention: I'd) '"can'rbe moved to an aexpanded position v.by .istarting tor 'iincreasing :the

;a retracted position :stopping iorrreducing the :rate of flow :nf ssaid :mud'tso that the positionrtof the .lcutters with .relation to the walliof the well is at all-.timestunder control-of the operator; (b) are each distinct .and separate from the other cutters, the force with which each cutter is forced .to cut' the wall =of the well being dependent solely ,upon .rate -.of W vof the mud and quite independentof the positionorcondition of-any'other .cutter. Since .these cutters are-each independently impelled andeach tpropelledoutwardly by the full pressure of the mud,.the number ofcutters can .be multiplied, as many as thirty-twp cutters .being .used .in .a 1 single underreamer.

The .resultsare accomplished by means of new methods of .mounting and moving .the cutters which maybe briefly described as follows: each cutteris carried ontheouterlend of:a'.piston;slid-- ingina cylindrical-opening in the lbodyiof the ,reamer, the .innerend of the piston being .subjected in .mud pressure.

The axis-of the piston ,is-in a directtion passing through the wall-of the well so that as the piston moves outwardly or away ,from the vertical axis of the well the cutters are forced into contact with and cut the wall of the well and thereby :rearn the hole. .I prefer to use cutters {of the :rotary toothed type which are old in the art but any -.other well knowniormofcutter may,-of-course,fbe used. 511 prefer to use stems coaxial-with the pistons and rigidly secured thereto which :pass through the wall of 'the'reamer'zbody and which'are'provided 'with means 'outsidethe body for limiting theout- 'ter described'or 'claimed'orto be claimed.

Certain features shown'here'in are shown "and claimed in my application-SerialNo. 670,932,filed May "20, .1946, the device shown in said application not being an unclerreamer but a simple reamerusedto smooth andrstra'ighten the hole. Referring to the drawings, which are for illustrative purposes only,

Fig. 11 is 'a view, partlyin section, of a reamer embodying my'invention;

Fig. Zisa section on'a plane represented by the ';line"22 of Fig.1;this planebeing viewed in the "direction'o'f thearrows adjacent the ends of that line;

Fig. 3 is an enlarged view of a cutter assemy;

Fig. 4 is a section on a plane represented by the line 44 of Fig. 2, this plane being viewed in the direction of the arrows adjacent the ends of that line;

Fig. 5 is a view of a portion of the reamer, a portion thereof being shown in section on a plane represented by the line 5-5 of Fig. 3, this plane being viewed in the direction of the arrows adjacent the ends of that line. In this view the cutter assembly is in expanded or maximum cutting position; and

Fig. 6 is a view similar to Fig. 4 with the cutter assembly in its retracted or minimum cutting position.

In my invention I may use the novel form of reamer shown in Figs. 1 to 6, inclusive. In the reamer shown in these drawings, I provide a body H] of cylindrical shape which is provided at its upper end with a frusto-conical cavity II which is threaded to receive the pin 2 of a tool joint I3, in which drill pipe I4 is threaded. The body It is somewhat smaller than the internal diameter of a casing |5 which may be cemented in the bore "5 of a well. The tool joint l3 has a central hole I! which connects the interior I8 of the drill pipe [4 with a central passageway |9 extending entirely through the body In of the reamer.

Slidably freely within limits in the bod H] are a plurality of cutter assemblies which may all be alike. Each section of the reamer may have eight cutter assemblies, and several sections such as that shown in the drawings may be coupled together to provide a reamer having sixteen or more cutter assemblies 20. Each cutter assembly consists of a piston 2| which is cylindrical about the axis 2222 of a cylindrical cavity 23 in the body H]. A cutter recess 24 of a shape best shown in Fig. 2 is cut transversely in the outer end of the piston 2|, leaving two bearing members 25. A pin 26 passes through the bearing members and carries a cutter 30. The cutter may be provided with teeth 21, as best shown in Fig. 2, or it may have teeth of an other shape now used in similar reamers. In a recess in the wall of the cavity 23 I place outer packing rin s 28, now known as O-rings and in general use in hydraulic installations. These O-rings allow the piston 2| to slide along the axis 2222 and prevent fluid from passing between the outer wall of the piston 2| and the inner wall of the cavity 23. Preferably formed integrally with the piston 2| is a cylindrical stop 3| and a tail bolt 32. The tail bolt passes through a hole 33 connecting the cavity 23 with a similar cavity 34 coaxial with the cavity 23, inner O-ri'n "s 35 being placed in the wall of the hole 33. The inner O-rin'rs 35 prevent fluid from escaping through the hole 33 around the bolt 32. Threaded on the outer end of the bolt 32 is a nut 36 which is held against rotation on the bolt 32 by a cotter pin 31.

The nut 36 limits the distance the cutter assembly 20 can move out of the body Ill, and the stop 3| limits the distance the assembly 2!] can move into the bod the total movement being indicated by the dimension a shown in Fig. 6.

With the cutter assembly in its retracted position as shown in Fig. 6, only a few of the teeth of the cutter project beyond the body i0, and in the expanded position of the cutter assembly as shown in Figs. 2 and 4, these teeth have moved outwardly through the radial distance a.

Preferably formed integrally with or welded to the piston 2| are four wings 40 which lit in slots 4| formed in the body l0 and best shown in Fig. 5. These wings 40 are separated by a distance I), which is a little in excess of the diameter of the pin 26, which may be inserted in and withdrawn from the bearings 25 through this space. The wings 40 are cut away at an angle, as shown at 42 in Fig. 4, so that if the reamer is pulled upwardly into the casing 15 the cutter assembly will be forced out of its expanded position, as shown in Fig. 4, into its retracted position, as shown in Fig. 6. Similarly, if the reamer is lowered into a small hole slightly larger than the body I0, the cutter assemblies will be forced into their retracted position. The parts are so proportioned that with the cutter assembly in its extreme expanded position the pin 26 is inside the recess 23, being held from moving farther outwardly by the nut 36. Upon loosening the nut, the piston 2| may be moved far enough out of the body In to enable the pin 26 to be withdrawn to replace the cutter 30.

Formed on the bottom of the body ID, as shown in Fig. 1, is a conical threaded pin 59, which is similar to the tool joint pin |2 and upon which a bit may be secured, the bit being fed with circulating drilling mud through the passage l9, the reamer when so used above the bit reaming the hole as fast as the bit cuts it. When used without a bit, that is, when used simply for reaming and straightening a previously drilled hole, a conical end 5| may be secured on the pin 50. This end 5| carries a bushing 52 having a hole 53 considerably smaller than the passage IS. The purpose of the small hole 53 is to cause pressure to build up in the passage l9 due to constriction of flow in the hole 53. Many bits have similar constricted openings which tend to also build up pressure, and, if not, the opening through which mud flows to the bit may be constricted by a bushing (not shown).

The passage I9 is first drilled through the body I0, and as the cavities 23 are formed they intersect the passage l9 so that the space below the piston 2| and between the O-rings 28 and is always in open communication with the passage |9. If, by constricting the flow of fluid below the reamer, pressure is built up in the passage I9 greater than the pressure of the fluid surroundin the body It), the piston forces each cutter assembly outwardly from the retracted position shown in Fig. 6 toward the expanded position shown in Figs. 2 and 4, this outward movement being limited by contact of the cutter 30 with the wall of the well, or where the well has been reamed to maximum diameter by the nut 36.

The reamer is put in operation by suspending the drill pipe l4 from the derrick and attaching the body 0 to the tool joint pin I2 on the bottom of the drill pipe. The bit, or conical, end 5| is then screwed onto the bottom of the body Hi. There being no fluid flowing through the passage l9, each of the cutter assemblies 20 can be readily pushed into retracted position, as shown in Fig. 6, and the reamer can be readily lowered through the casing 5 until the reamer is below the lower end of this casing. The drill pipe is then rotated and the mud pump is started and mud flows downwardly through the drill pipe l4 and through the central passage H] in the body [0. This flow being restricted below the reamer, pressure builds up in the passage l9, and this pressure is transmitted equally anduniformly to all of the pistons 2|, forcing tlieui all outwardly with equal force imitil the cutters ll bear 'o'n' ti'ie" inner wall-of the well and milk thereon, "cutting-thiswall bythe action of the teeth on the cutters' 3ll, in a manner -"wel1"known in the drilling --art in which such toothed drilling cutters have longbeen usedin :drilling bits. The 'reamer is 'slowly lowered in th-e Well, and each *cutter progressively *from top to bottom acts to 'cutor break off: material from-the walls I until the maximumdiameten of well bore is produced, when the upper cutters are =rendered inoperative, further "outward travel being=stopped by the 'nuts36. When the =reamer is removed from the well, the teethof the lower cutters 5 2i will befound to be bluntedor-worn. lIf the upper cutters are found to be without such weanfthisf is an indication that 'the'hole has been reamed to maximumdiameter. Ii all the cutters are :found to be equally worn, it is 'equally obviousthatafull "hole has not beencutjbut with "atwo-section "reamer, or with sixteen cutters above theibit, the 'reamer will usually ream more 'hole -thanany'o'f the'present bits -willmake, and there "will -ordi- -narily be very little wear 'on-the cutters of the 111 p er reamer section.

When it is desired to remove'the' reamer'from the hole, rotation and circulation of fluid is stopped, and there is'nowno pressure forcing the cutter assemblies ZOoutWardly. As the Lreamer enters-the casing ltgeach cutter assembly .:is forced back into the body by the'inclinedsurfaces 42 of the wings --4ll,' s'triking the casing i5or the wall of the well just'below the 'casing and the 1 reamer moves freely in its upward Itrip through I the casing.

As soon as the'reamer emerges fromthezwell, the cutters '21 are inspected "for'wearyandtany 'cuttersshowing undue:wear-"arereplacedwith-the reamer hanging in place. "The replacement-of a cutter involves'removing the cotter pin fil and backing the nut ofi "to allow-the cutter; headztozbe -*moved out far enough 'to allow theipin lfifiitozbe removed, thusreleasingthe worn cutter-121..

..A sharp cutter is then putin place:and ainewzpirr is supplied. The nut 36 is then: screwedihome, ithe cotter pin '31 isu'eplace'd, and'the 'reameriis ready for another trip into the hole. The cutters #9 and pins'3'5 will show considerable wear and must be frequently replaced, but none of the other parts except'the bus'hing'53, which tends to be cut by lhigh velocity mud, \will wear .materiallypver I by the bit. Thisresults in-a smooth hole-"of uniform and greater diameter than the inside of the casing l5.

One great advantage of my reamer is that it can be used to ream upwardly. In other words, it can be dropped to the bottom of a small hole and, when rotated during its travel in an upward direction, will ream hole to maximum diameter back to the casing I5.

I claim as my invention:

1. In an underreamer for use in wells of the itype 'gin which a body attached': torafdrillingrstring -composecl o'f sections of drill pipe is rotated i by rsaid string and carriesa cutteror cutters-which may "be expanded and pushed outwardly to con- :tacttand 'cut the wa'llot the well or retracted and pulled inwardly'to aposition which allows thenunderreamer to ':be withdrawn through casing of c-smaller diameter 'than the hole produced below the "casing by the -reamer, 'the combination of such a 'body having a: circulationchannel through which-a liquid such asrotary mud may he forced :downwardly from the: drill pipe, said liquidflow -in"g upwardly at a reduced' pressure through the *spa'cebetween'the body and the wall of the well, said 'body' having a cylindrical bore therein which .is in open communication with said circulation channel, the axis of said borepassing through the "wall of thewell' when sai'd'body is in working =pos'ition*therein; a piston which is free 'to move :"alongthe axis-of said bore, saidpiston being so q'alaced in said -bore "that it tends to prevent-=said "liquid w'from *escaping -from said channel and '"through saidboreinto the well; a'cutter'spindle -'carried *by the ou'terend of said piston; and 7a 'toothed cutter free to revolve on said spindle, *sa-i'dspindle-being so placed with relation to said piston thatthe teeth of said cutter are forced into *cutting rela'tion to the wallo'f the well when said piston moves along said axistoward said wall.

2.In an underreamer for use'in wells-of the -Ltype in which abody attached-to a drilling string composed of =sections of drill pipe is rotated by *said string'and carries-a cutter or cutters-which may beexpanded'and pushed outwardly tocontactand out the wall'of the well or retracted and pulled inwardly to a position which allows the urnderreamer to be *withdrawn through casing of smaller diameter than the hole produced below the casing by the 'reamer, the combination of: 'sucha body having'a circulation channel through which a liquid-such as rotary mud may be forced downwardlydrom the drill pipe, said liquid flow- 'ing upwardly at a reduced pressure through the space between the body and the wall of the well, said'body having a cylindrical bore therein which -is in open communication with said circulation channel, the axis of said bore passing through thewall of th well when'saidbody is in working positiontherein; a piston which is free to move "along the axis of said'bore, said 'pistonbeing so "place'din-said bore that-itt'ends to prevent said liquid "from escaping from said channel and through said bore into the well; a stem attached v -to said piston and concentricwith the axis of said piston, said-stem extending in fluid-tight relationship through an opening in ;the wall of said ibody, :said opening being concentric with the raxi'siof. said bore. and 'extendingthrough the wall rof the sbody .in a direction'axially :opposite tosaid ibore; :fasteriingimeanson th outer'end of said stem :oLIarger'diameter than said stemand said stemopening;: and a :cuttencarrled by said piston sand :so placed that said :cutter .is .iorced against zandzcuts .the wall :of .the well when said piston !inoves:along saidzi-axis towardsaidwall.

. &3.";In:annnderreamer zfor'usein Wells .of the type in which a body attached to a drilling string composed of sections of drill pipe is rotated by said string and carries a cutter or cutters which may be expanded and pushed outwardly to contact and cut the wall of the well or retracted and pulled inwardly to a position which allows the underreamer to be withdrawn through casing of smaller diameter than the hole produced below the casing by the reamer, the combination of:

such a body having a circulation channel through which a liquid such as rotary mud may be forced downwardly from the drill pipe, said liquid flowing upwardly at a reduced pressure through the space between the body and the wall of the well; said body having a cylindrical bore therein which is in open communication with said circulation channel, the axis of said bore passing through the wall of the well when said body is in working position therein; a piston which is free to move along the axis of said bore, said piston being so placed in said bore that it tends to prevent said liquid from escaping from said channel and through said bore into the well; a stem attached to said piston and concentric with the axis of said piston, said stern extending in fluid-tight relationship through an opening in the wall of said body, said opening being concentric with the axis of said bore and extending through the wall of the body in a direction axially opposite to said bore; fastening means on the outer end of said stem of larger diameter than said stem and said stem opening; a cutter spindle carried by the outer end of said piston; and a toothed cutter free to revolve on said spindle, said spindle being so placed with relation to said piston that the teeth of said cutter are forced into cutting relation to the wall of the well when said piston moves along said axis toward said wall.

4. In an underreamer for use in wells of the type in which a body attached to a drilling string composed of sections of drill pipe is rotated by said string and carries a cutter or cutters which may be expanded and pushed outwardly to contact and cut the wall of the Well or retracted and pulled inwardly to a position which allows the underreamer to be withdrawn through casing of smaller diameter than the hole produced below the casing by the reamer, the combination of:

such a body having a circulation channel through which a liquid such as rotary mud may be forced downwardly from the drill pipe, said liquid flowing upwardly at a reduced pressure through the space between the body and the wall of the well, said body having a cylindrical bore therein which is in open communication with said circulation channel, the axis of said bore passing through the wall of the well when said body is in working position therein; a piston which is free to move along the axis of said bore, said piston being so placed in said bore that it tends to prevent said liquid from escaping from said channel and through said bore into the well, a member so placed as to prevent said piston from turning about the axis of said piston in said bore but which allows the piston to slide freely therein; a stem attached to said piston and concentric with the axis of said piston, said stem extending in fluid-tight relationship through an opening in the wall of said body, said opening being concentric with the axis of said bore and extending through the wall of the body in a direction axially opposite to said bore; fastening means on the outer end of said stem of larger diameter than said stern and said stem opening; and a cutter carried by said piston and so placed that said cutter is forced against and cuts the wall of the well when said piston moves along said axis toward said wall.

5. In an underreamer for use in wells of the type in which a body attached to a drilling string composed of sections of drill pipe is rotated by said string and carries a cutter or cutters which may be expanded and pushed outwardly to contact and cut the wall of the well or retracted and pulled inwardly to a position which allows the underreamer to be withdrawn through casing of smaller diameter than the hole produced below the casing by the reamer, the combination of such a body having a circulation channel through which a liquid such as rotary mud may be forced downwardly from the drill pipe, said liquid flowing upwardly at a reduced pressure through the space between the body and the wall of the well; said body having a cylindrical bore therein which is in open communication with said circulation channel, the axis of said bore passing through the wall of the well when said body is in working position therein; a piston which is free to move along the axis of said bore, said piston being so placed in said bore that it tends to prevent said liquid from escaping from said channel and through said bore into the well; a member so placed as to prevent said piston from turning about the axis of said piston in said bore but which allows the piston to slide freely therein; a stem attached to said piston and concentric with the axis of said piston, said stem extending in fluid-tight relationship through an opening in the wall of said body, said opening being concentric with the axis of said bore and extending through the wall of the body in a direction axially opposite to said bore; fastening means on the outer end of said stem of larger diameter than said stem and said stem opening; a cutter spindle carried by the outer end of said piston; and a toothed cutter free to revolve on said spindle, said spindle being so placed with relation to said piston that the teeth of said cutter are forced into cutting relation to the wall of the well when said piston moves along said axis toward said wall.

FORD W. HARRIS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 789,867 McCallum May 16, 1905 1,359,699 Hauser Nov. 23, 1920 1,565,788 Carlson Dec. 15, 1925 1,594,668 Gates et a1 Aug. 3, 1926 1,786,484 Duda Dec. 30, 1930 1,801,424 Gray Apr. 21, 1931 1,893,693 Aloi Jan. 10, 1933 2,053,829 Hise Sept. 8, 1936 2,110,582 Smith Mar. 8, 1938 2,126,146 Smith Aug. 9, 1938 2,4 8.673 McMahan Mar. 30. 1948 

